Cell Phone Use and Susceptibility to Brain Tumors in Children

Summary
Cell phone usage has been suspected to lead to risk of brain tumors, especially in children and adolescents. This study analyzes reported cases of brain tumor and assesses the likely association with events and duration of talking on cell phones. Statistical evidence did not support regular cell phone use as a potential risk factor for brain tumors. Moreover, no significant match was observed between the exposure to mobile radiation and the location of tumor. Hence, a direct causal link was not recorded. However, further examination is essential to completely rule out the association.

Introduction
Recent times have witnessed widespread use and ownership of cell phones, even in school-aged children. It has been established that the brain tissue of children in growing age is more conductive than in adults. This triggers the possibility of higher absorption and penetration of electromagnetic radiation emitted from mobile phones. However, research has also explained that the radio frequency arising from mobile phones is not strong enough to cause DNA damage. Heating is the only known effect of this radiation. The present study is one of the first efforts to evaluate the relation between mobile phone use and cancer in children. This association has already been ruled out in adults, barring a few stray cases.

Methodology
* The CEFALO study is an international case-control study looking at the association between the use of mobile phones and the risk of brain tumors in adolescents and children.
* Interviews were conducted with 352 patients, aged 7 to 19, diagnosed with confirmed brain tumor, and 646 control subjects, both from the CEFALO study, conducted in Denmark, Sweden, Norway, and Switzerland.
* Details of cell phone use, period and nature of subscription, duration of calls, use of hands-free devices, side of head used, and other possible radiation sources were noted.
* All the above data were correlated and analyzed for possible risk of brain tumor due to the continuous use of mobile phones.

Results/Key findings
* Routine mobile phone use was reported in 55 percent of tumor patients and 51 percent of control subjects. There was no significant difference in mobile phone usage between the two groups. Thus, no definite causal relationship was established.
* Higher radiation exposure to the temporal, frontal lobes, and cerebellum did not correspond with higher risk, while areas of lesser exposure recorded more tumors. The risk in those who used the mobile phone on both sides of the head was similar to those who used one side.
* Short-term mobile phone usage does not trigger tumors.
* However, longer subscription periods showed increased risk.

Next Steps/Shortcomings
Complete details of subscription periods were not obtained. Interviews with children themselves led to limitations on thorough data on hands-free use and details of whether the children or someone else took their calls. Minor risk contributions were not effectively accounted for, due to the limited statistical power of the study. Developments in mobile technology could have either increased or decreased radio frequency exposure post-CEFALO.

Conclusion
This study establishes quite strongly that no significant association has emerged between mobile phone usage and brain tumors in children. However, some small doubts creep in with respect to prolonged subscription time. Physiologically, the areas of brain exposed to radiation did not match with tumor-affected areas. The strength of this study was the absence of selection bias, as there was a good representation of mobile phone users. Thus, the direct causality of tumor can be attributed neither to length of mobile phone usage nor region of radio frequency exposure. Nevertheless, further studies are warranted to weed out any suspicion of risk arising from smaller events, especially in view of the upward trend in usage of mobile phones by children and adolescents across the world.